JP4243335B2 - Progressive power lens - Google Patents

Description

【数１４】

【００２３】
但し、上記条件（１）、（２）において、遠用部の屈折力と近用部の屈折力の差である加入度数をＡＤ（単位：ディオプター）としたときに、Ｗ_ｄｔは、遠用部内において幾何学中心から上方に所定距離離れた高さでの透過非点収差がＡＤ／２となる領域の水平方向の幅を表す。Ｗ_ｎｔは、近用部内において幾何学中心から下方に所定距離離れた高さでの透過非点収差がＡＤ／２となる領域の水平方向の幅を表す。Ｗ_ｄｓは、遠用部内において幾何学中心から上方に所定距離離れた高さでの面非点収差がＡＤ／２となる領域の幅を表す。Ｗ_ｎｓは、近用部内において幾何学中心から下方に所定距離離れた高さでの面非点収差がＡＤ／２となる領域の幅を表す。以下の本文において示す各条件についても同様である。
【００２４】
このように、遠用部と近用部における面非点収差と透過非点収差の関係を決めることにより、透過非点収差を低くおさえ、装用者の実質的な視野である明視域を広く確保することができる。さらには、眼鏡の美的外観を良好に保つために特定の遠用部の度数に対して複数種類のベースカーブが用意されており、かつ透過性能での収差バランスが統一された累進屈折力レンズシリーズを構成するための累進屈折力レンズを提供することができる。このレンズシリーズに属する累進屈折力レンズによれば、左右のレンズの収差バランスを略一致させることにより、左側のレンズを介した見え方と右側のレンズを介した見え方が略同じとなる眼鏡が提供される。なお、特許文献１〜特許文献４のいずれにも、眼鏡レンズにおいて重要な性能といえる非点収差の面評価と透過評価との上記定量的関係に関する言及がなされていない。従って、どの文献に基づいても本発明のような透過非点収差のバランスが統一された累進屈折力レンズシリーズを実現することは不可能である。
【００２５】
なお、レンズの基本的仕様としては、遠用部球面屈折力Ｓｐｈ（単位：ディオプター）、遠用部の屈折力と近用部の屈折力の差である加入度数ＡＤ（単位：ディオプター）、累進帯長Ｌ（単位：ミリ）などが例示される。
【００２６】
上記累進屈折力レンズは、球面屈折力Ｓｐｈ（単位：ディオプター）が＋１以上である場合、さらに以下の条件（３）を満たし、該球面屈折力Ｓｐｈが−１以下である場合、さらに以下の条件（４）を満たすことができる。
【００２７】
【数１５】

【数１６】

【００２８】
ベースカーブが比較的浅めの場合には、面非点収差と透過非点収差は、上記条件（３）、（４）を満たすと好適である。
【００２９】
また、別の観点から、本発明に係る累進屈折力レンズは、少なくともレンズの一方の面が、遠方を見るための屈折力を持つ遠用部、近方を見るための屈折力を持つ近用部、および漸進的に屈折力が変化し遠用部と近用部の屈折力を連続的に接続する中間部を備える累進面であり、所定の光学性能を有するレンズを基準として設計された、複数種類のベースカーブを持つ一連の累進屈折力レンズシリーズに属する累進屈折力レンズにおいて、該シリーズの中から任意に抽出された第１レンズのベースカーブをＢＣ_１、第２レンズのベースカーブをＢＣ_２（但しＢＣ_１＜ＢＣ_２とする）とし、第１レンズおよび第２レンズの遠用部の球面屈折力Ｓｐｈ（単位：ディオプター）が＋１以上である場合に以下の条件（５）を満たし、該球面屈折力Ｓｐｈが−１以下である場合に以下の条件（６）を満たすことを特徴とする。
【００３０】
【数１７】

【数１８】

【００３１】
このように、遠用部と近用部における面非点収差の配置を決めることにより、透過性能での非点収差を低くおさえ、装用者の実質的な視野である明視域を広く確保することができる。加えて、眼鏡の美的外観を良好に保つために特定の遠用部の度数に対して複数種類のベースカーブが用意されており、かつ透過性能での収差バランスが統一された累進屈折力レンズシリーズを構成するための累進屈折力レンズを提供することができる。
【００３２】
さらに別の観点から、本発明の累進屈折力レンズは、少なくともレンズの一方の面が、遠方を見るための屈折力を持つ遠用部、近方を見るための屈折力を持つ近用部、および漸進的に屈折力が変化し遠用部と近用部の屈折力を連続的に接続する中間部を備える累進面であり、所定の光学性能を有するレンズを基準として設計された、複数種類のベースカーブを持つ一連の累進屈折力レンズシリーズに属する累進屈折力レンズにおいて、該シリーズの中から任意に抽出された第１レンズのベースカーブをＢＣ_１、該第１レンズの遠用部の球面屈折力をＳｐｈ_１（単位：ディオプター）、第２レンズのベースカーブをＢＣ_２、該第２レンズの遠用部の球面屈折力をＳｐｈ_２（単位：ディオプター）とすると、ＢＣ_１≠ＢＣ_２またはＳｐｈ_１≠Ｓｐｈ_２である場合に、以下の条件（７）を満たすことを特徴とする。
【００３３】
【数１９】

【００３４】
条件（７）のように、遠用部と近用部における透過非点収差の分布を決めることにより、透過の非点収差を低くおさえ、装用者の実質的な視野である明視域を広く確保することができる。さらに、眼鏡の外観を良好に保つためにベースカーブを変化させたり、仕様に応じて遠用部球面屈折力を変化させたりした場合であっても収差バランスが統一された累進屈折力レンズシリーズに属する累進屈折力レンズが提供される。
【００３５】
上記条件（７）において、第１レンズの遠用部の球面屈折力Ｓｐｈ_１と第２レンズの遠用部の球面屈折力Ｓｐｈ_２をともに同一値Ｓｐｈ_ｆに固定した場合、累進屈折力レンズは以下の条件（８）を満たす。
【００３６】
【数２０】

【００３７】
さらに、条件（８）を満たす累進屈折力レンズにおいて、上記Ｓｐｈ_ｆが０よりも小さい値を採る場合には、以下の条件（９）も満たす。
【００３８】
【数２１】

【００３９】
上記条件（７）において、第１レンズのベースカーブＢＣ_１と第２レンズのベースカーブＢＣ_２をともに同一値ＢＣ_ｆに固定した場合、累進屈折力レンズは以下の条件（１０）を満たす。
【００４０】
【数２２】

【００４１】
上記の各累進屈折力レンズにおいて、中間部の長さ、すなわち累進帯長を１５ｍｍ以上３０ｍｍ以下とすることが望ましい。累進帯長を１５ｍｍ以上と長く設定することにより、中間部明視域幅を広くでき、かつ累進帯側方、つまりレンズにおける左側領域と右側領域での非点収差の発生を抑えることが可能となる。また、累進帯長を３０ｍｍ以下とすることにより、遠方から近方に視線を移動する際の目の回旋角が小さくなり、使用者の目の負担を軽減することができる。結果として揺れや歪みが少なく、長時間の使用でも疲れにくい累進屈折力レンズを提供することができる。
【００４２】
また、上記の各累進屈折力レンズにおいて、レンズ内面を累進面とすることが望ましい。レンズ内面とはすなわち眼鏡装用者の眼側の面のことである。累進面を内面にすることにより、外面は球面加工を施すだけでよくなる。これにより、加入屈折力、累進帯長の違いごとに外面の型を多数用意する必要がなくなるため、製造にかかる負担を軽減し、製造コストを大幅に削減することが可能になる。
【００４３】
ここで、遠用部内において幾何学中心から所定距離離れた位置は、遠用部測定基準点と略一致し、近用部内において幾何学中心から所定距離離れた位置は、近用部測定基準点と略一致することができる。上記所定距離としては、１５ｍｍが好ましい。
【００４４】
本発明にかかる累進屈折力レンズは、以下の構成をとることを特徴とする。すなわち、少なくともレンズの一方の面が、遠方を見るための屈折力を持つ遠用部、近方を見るための屈折力を持つ近用部、および漸進的に屈折力が変化し遠用部と近用部の屈折力を連続的に接続する中間部を備える累進面である累進屈折力レンズにおいて、遠用部の屈折力と近用部の屈折力の差である加入度数をＡＤ（単位：ディオプター）としたときに、幅Ｗ_ｄｔと幅Ｗ_ｎｔが以下の条件（１１）を満たすように設計されることを特徴とする。
【００４５】
【数２３】

【００４６】
このように、遠用部と近用部における透過非点収差の分布を決めることにより、透過の非点収差を低く抑え、装用者の実質的な視野である明視域を広く確保し、特に室内や卓上での作業時に優れた装用感が得られる中近用累進屈折力レンズを実現することができる。
【００４７】
近方にある物体の観察に重点をおいた中近用累進屈折力レンズや近用累進屈折力レンズを製造するのであれば、以下の条件（１２）を満たすように設計して近用部の面積を広くすると好ましい。
【００４８】
【数２４】

【００４９】
上記条件（１１）や（１２）を満たす累進屈折力レンズにおいても、中間部の長さ、すなわち累進帯長を１５ｍｍ以上３０ｍｍ以下とすることが望ましい。累進帯長を１５ｍｍ以上と長く設定することにより、中間部明視域幅を広くでき、かつ累進帯側方、つまりレンズにおける左側領域と右側領域での非点収差の発生を抑えることが可能となる。また、累進帯長を３０ｍｍ以下とすることにより、遠方から近方に視線を移動する際の目の回旋角が小さくなり、使用者の目の負担を軽減することができる。結果として揺れ歪みが少なく、長時間の使用でも疲れにくい累進屈折力レンズを提供することができる。また該累進屈折力レンズにおいても、レンズの加工の容易性から、レンズ内面を累進面とすることが望ましい。
【００５０】
【発明の実施の形態】
【００５１】
図１は本発明の第１実施形態における累進屈折力レンズ１０の透過性能での非点収差分布（図１Ａ）と平均屈折力分布（図１Ｂ）を表す。図中の等高線の間隔はいずれも０．５ディオプターごとに表示したものであり、以下に示す各分布図でも同様である。なお、以下の説明では、累進屈折力レンズ１０の直径は６０ｍｍであるとする。図２は、図１に示す累進屈折力レンズ１０の面性能での非点収差分布（図２Ａ）と平均屈折力分布（図２Ｂ）を表す。図１Ａに示す透過非点収差分布は、累進屈折力レンズ１０の全加工領域および全ての点でのベースカーブにおいて、一連の累進屈折力レンズシリーズに属するレンズが備える光学性能の目標値となる。つまり、累進屈折力レンズ１０は、一連の累進屈折力レンズシリーズにおける基準として設計されたレンズである。
【００５２】
第１実施形態の基準設計となる累進屈折力レンズ１０は、遠用部球面屈折力Ｓｐｈが０．０ディオプター、加入度数ＡＤが２．０ディオプター、ベースカーブＢＣが３．２１ディオプターの、いわゆる中近用累進屈折力レンズである。累進帯はレンズ幾何学中心Ｏの上方１１ｍｍから加入が始まり、該中心Ｏの下方８ｍｍで終わる。従って、累進帯長（中間部の長さ）は１９ｍｍである。
【００５３】
図３は、累進屈折力レンズ１０における透過性能の特徴量を説明する図である。図４は、累進屈折力レンズ１０における面性能の特徴量を説明する図である。図３、図４において左右基準線Ｘと上下基準線Ｙはそれぞれ幾何学中心Ｏを通り、互いに直交する方向に延出する。左右基準線Ｘの延出方向は水平方向と略一致し、上下基準線Ｙの延出方向は鉛直方向と略一致する。また、主注視線ＧＬは、中間部から近用部にかけて鼻側に偏位している。
【００５４】
図３に示す２本の曲線ＡＬｔは、透過非点収差が加入度数ＡＤの１／２となっている等高線を表す。累進屈折力レンズ１０において、Ｗ_ｄｔ（単位：ミリ）は幾何学中心Ｏを含む左右基準線Ｘから鉛直方向にＤＬ（単位：ミリ）だけ上方の高さにおける２本の曲線ＡＬｔ間の水平方向幅を表す。同様にＷ_ｎｔ（単位：ミリ）は左右基準線Ｘから鉛直方向にＮＬ（単位：ミリ）だけ下方の高さにおける２本の曲線ＡＬｔ間の水平方向幅を表す。累進屈折力レンズ１０では、２本の曲線ＡＬｔ間を明視域と規定する。
【００５５】
図４に示す２本の曲線ＡＬｓは、面非点収差が加入度数ＡＤの１／２となっている等高線を表す。Ｗ_ｄｓ（単位：ミリ）は幾何学中心Ｏから上下基準線Ｙに沿ってＤＬだけ上方の高さにおける２本の曲線ＡＬｓ間の水平方向幅を表す。同様にＷ_ｎｓ（単位：ミリ）は幾何学中心Ｏから上下基準線Ｙに沿ってＮＬだけ下方の高さにおける２本の曲線ＡＬｓ間の水平方向幅を表す。
【００５６】
なお、累進屈折力レンズ１０では、ＤＬは、主注視線上において、左右基準線Ｘから遠用度数測定点までの距離に略等しく設定される。またＮＬは、主注視線上において、左右基準線Ｘから近用度数測定点までの距離に略等しく設定される。そのため、本実施形態では、上記ＤＬおよびＮＬをそれぞれ１５ｍｍに設定する。従って、ＷｄｔやＷｄｓは遠用部における２本の曲線ＡＬｔまたはＡＬｓ間の水平方向幅を意味し、ＷｎｔやＷｎｓは、近用部における２本の曲線ＡＬｔまたはＡＬｓ間の水平方向幅を意味する。
【００５７】
ＤＬおよびＮＬをそれぞれ１５ｍｍに設定すると、累進屈折力レンズ１０の透過非点収差分布および面非点収差分布において、非点収差が加入度数ＡＤの１／２となる領域幅（Ｗ_ｄｔ、Ｗ_ｎｔ、Ｗ_ｄｓ、Ｗ_ｎｓ）を検証すると、以下の特徴が導出される。
【００５８】
具体的には、累進屈折力レンズ１０を基準設計とする一連の累進屈折力レンズシリーズから任意に二つのレンズ（第１レンズ、第２レンズ）を抽出したとする。そして該二つのレンズの、Ｗ_ｎｔとＷ_ｄｔの比、およびＷ_ｄｓとＷ_ｎｓの比をそれぞれ求める。次いで、第１レンズと第２レンズともに特定の遠用部球面屈折力Ｓｐｈであって各レンズのベースカーブが変化する場合における、Ｗ_ｎｔとＷ_ｄｔの比およびＷ_ｄｓとＷ_ｎｓの比の関係を調べる。すると、遠用部球面屈折力Ｓｐｈが＋１以上である場合に以下の条件（１）が成立し、該球面屈折力Ｓｐｈが−１以下である場合に以下の条件（２）が成立する。
【００５９】
【数２５】

【数２６】

但し、ＢＣ_１は第１レンズのベースカーブを表し、ＢＣ_２は第２レンズのベースカーブを表す。そして、ＢＣ_１＜ＢＣ_２である。
【００６０】
さらに、レンズを薄くするように比較的浅いベースカーブを選択した場合には、Ｗ_ｎｔとＷ_ｄｔの比およびＷ_ｄｓとＷ_ｎｓの比を比較した値は、遠用部球面屈折力Ｓｐｈが＋１ディオプターより大きい範囲では以下の条件（３）を満たし、該球面屈折力が−１ディオプターより小さい範囲では以下の条件（４）を満たす。
【００６１】
【数２７】

【数２８】

【００６２】
また一連の累進屈折力レンズシリーズから任意に抽出された第１レンズと第２レンズの面性能のみに着目する。そして第１レンズと第２レンズがともに特定の遠用部球面屈折力であって各レンズのベースカーブが変化する場合における、各レンズのＷ_ｄｓとＷ_ｎｓの比を調べる。すると、第１レンズおよび第２レンズの遠用部球面屈折力Ｓｐｈが＋１以上である場合には以下の条件（５）が成立する。また、該球面屈折力Ｓｐｈが−１以下である場合には以下の条件（６）が成立する。
【００６３】
【数２９】

【数３０】

但し、ＢＣ_１＜ＢＣ_２である。
【００６４】
第１レンズおよび第２レンズの面設計を、条件（５）、（６）が成り立つように行うことによって、透過性能を高めつつも、美的外観を損なうことなく、収差バランスが全体として統一された眼鏡レンズが提供される。
【００６５】
また一連の累進屈折力レンズシリーズから任意に抽出された第１レンズと第２レンズの透過性能のみに着目して各レンズのＷ_ｄｔとＷ_ｎｔの比を調べる。すると、第１レンズと第２レンズの双方におけるベースカーブと遠用部球面屈折力のいずれかが変化する場合には、条件（７）が成り立つ。第１レンズと第２レンズがともに特定の遠用部球面屈折力Ｓｐｈ_ｆであって各レンズのベースカーブが変化する場合には、条件（８）が成り立つ。条件（８）が成立するときに、遠用部球面屈折力Ｓｐｈ_ｆがマイナスである場合、第１レンズと第２レンズは、さらに条件（９）を満たす。第１レンズと第２レンズがともに特定のベースカーブＢＣ_ｆであって各レンズの遠用部球面屈折力が変化する場合には、条件（１０）が成り立つ。
【００６６】
【数３１】

【数３２】

【数３３】

【数３４】

【００６７】
第１レンズおよび第２レンズの透過性能を、ベースカーブ、遠用部球面屈折力の変化に対し、上記の各条件（８）〜（１０）のいずれかを満たすように設計することにより、明視域幅を眼鏡の仕様に応じてコントロールする。これにより、装用状態における光学性能を良好にし、かつ美的外観に優れた累進屈折力レンズを実現することができる。
【００６８】
一連の累進屈折力レンズシリーズに属する累進屈折力レンズ単体（例えば累進屈折力レンズ１０）に着目した場合、該レンズの透過性能における幅Ｗ_ｄｔと幅Ｗ_ｎｔの比は、条件（１１）を満たす。
【００６９】
【数３５】

【００７０】
遠用部の明視域幅と近用部の明視域幅との関係が、条件（１１）を満たすように設計された累進屈折力レンズは、透過性能が高い中近用累進屈折力レンズである。そして該累進屈折力レンズを装用する者は、特に室内や卓上での作業時に優れた装用感を得ることができる。
【００７１】
図５は、累進屈折力レンズ１０を基準設計とする一連の累進屈折力レンズシリーズに属するいくつかの累進屈折力レンズに関する、透過非点収差分布と透過平均屈折力分布、および面非点収差分布と面平均屈折力分布の一覧である。図５に示す各累進屈折力レンズは、遠用部球面屈折力Ｓｐｈが＋２．００ディオプターで共通となっており、加入度数ＡＤが２．０ディオプターであり、ベースカーブＢＣを図中の上から２．４３、３．２１、４．１６、４．７８、５．６９、６．４８（単位は全てディオプター）と変化させたものである。図６は遠用部球面屈折力Ｓｐｈがプラス範囲に設定されたときに、上記（Ｗ_ｄｓ／Ｗ_ｎｓ）／（Ｗ_ｄｔ／Ｗ_ｎｔ）がベースカーブの変化に対しどのように変化するかを示すグラフである。図７は、遠用部球面屈折力Ｓｐｈがプラス範囲に設定されたときに、上記Ｗ_ｄｓ／Ｗ_ｎｓがベースカーブの変化に対しどのように変化するかを示すグラフである。図５〜図７に示す収差図およびグラフから分かるように、ベースカーブが変化しても、透過非点収差はほぼ同一の分布傾向を示している。また、どの累進屈折力レンズも累進屈折力レンズ１０とほぼ同一の収差分布であることから、高い光学性能を備えている。
【００７２】
図６から、累進屈折力レンズ１０を基準設計とする一連の累進屈折力レンズシリーズに属するレンズは、条件（１）を満たすことがわかる。また、同レンズは、条件（３）も満たしている。また、図７から、累進屈折力レンズ１０を基準設計とする一連の累進屈折力レンズシリーズに属するレンズは、Ｓｐｈ＋４.００の場合には、条件（５）も満たすことがわかる。
【００７３】
図８は、累進屈折力レンズ１０を基準設計とする一連の累進屈折力レンズシリーズに属するいくつかの累進屈折力レンズに関する、透過非点収差分布と透過平均屈折力分布、および面非点収差分布と面平均屈折力分布の一覧である。図８に示す各累進屈折力レンズは、遠用部球面屈折力Ｓｐｈが−２．００ディオプターで共通となっており、加入度数ＡＤが２．０ディオプターであり、ベースカーブＢＣを図中の上から１．６２、２．４３、３．２１、４．１６、４．７８、５．６９（単位は全てディオプター）と変化させたものである。図９は、遠用部球面屈折力Ｓｐｈがマイナス範囲に設定されたときに、上記（Ｗ_ｄｓ／Ｗ_ｎｓ）／（Ｗ_ｄｔ／Ｗ_ｎｔ）がベースカーブの変化に対しどのように変化するかを示すグラフである。図１０は、遠用部球面屈折力Ｓｐｈがマイナス範囲に設定されたときに、上記Ｗ_ｄｓ／Ｗ_ｎｓがベースカーブの変化に対しどのように変化するかを示すグラフである。図８〜図１０に示す収差図やグラフから分かるように、ベースカーブが変化しても、透過非点収差はほぼ同一の分布傾向を示している。また、どの累進屈折力レンズも累進屈折力レンズ１０とほぼ同一の収差分布であることから、高い光学性能を備えている。
【００７４】
図９から、累進屈折力レンズ１０を基準設計とする一連の累進屈折力レンズシリーズに属するレンズは、条件（２）を満たすことがわかる。Ｓｐｈを−２．００、−４.００に設定したときには、どのレンズを任意に抽出しても条件（４）を満たすこともわかる。また、図１０から、累進屈折力レンズ１０を基準設計とする一連の累進屈折力レンズシリーズに属するレンズは、Ｓｐｈ−２.００、−４.００では条件（６）も満たすことがわかる。
【００７５】
図１１は累進屈折力レンズ１０を基準設計とする一連の累進屈折力レンズシリーズに属するいくつかの累進屈折力レンズに関する、透過非点収差分布と透過平均屈折力分布、および面非点収差分布と面平均屈折力分布の一覧である。図１１に示す各累進屈折力レンズは、ベースカーブが４．１６ディオプターで共通となっており、加入度数ＡＤが２．０ディオプターであり、遠用部球面屈折力を図中の上から−４．００、−２．００、０．００、＋２．００、＋４．００（単位は全てディオプター）と変化させたものである。図１２は、上記Ｗ_ｄｔ／Ｗ_ｎｔがベースカーブの変化に対しどのように変化するかを示すグラフである。図１１に示す収差図および図１２に示すグラフから分かるように、遠用部球面屈折力が変化しても、また、ベースカーブが変化しても透過非点収差はほぼ同一の分布傾向を示している。また、どの累進屈折力レンズも累進屈折力レンズ１０とほぼ同一の収差分布であることから、高い光学性能を備えている。
【００７６】
図１２に示すグラフより、累進屈折力レンズ１０を基準設計とする一連の累進屈折力レンズシリーズに属するレンズは、条件（７）〜（１１）を満たすことがわかる。
【００７７】
図１３は本発明の第２実施形態における累進屈折力レンズ２０の透過性能での非点収差分布（図１３Ａ）と平均屈折力分布（図１３Ｂ）を表す。図中の等高線の間隔はいずれも０．５ディオプターごとに表示したものであり、以下に示す各分布図でも同様である。なお、以下の説明では、累進屈折力レンズ２０の直径は６０ｍｍであるとする。図１４は、図１３に示す累進屈折力レンズ２０の面性能での非点収差分布（図１４Ａ）と平均屈折力分布（図１４Ｂ）を表す。図１３Ａに示す透過非点収差分布は、累進屈折力レンズ２０の全加工領域および全ての点でのベースカーブにおいて、一連の累進屈折力レンズシリーズに属するレンズが備える光学性能の目標値となる。つまり、累進屈折力レンズ２０は、一連の累進屈折力レンズシリーズにおける基準として設計されたレンズである。
【００７８】
第２実施形態の基準設計となる累進屈折力レンズ２０は、遠用部球面屈折力Ｓｐｈが０．０ディオプター、加入度数ＡＤが２．０ディオプター、ベースカーブＢＣが４.１６ディオプターのいわゆる近用累進屈折力レンズである。累進帯はレンズ幾何学中心Ｏの上方１１ｍｍから加入が始まり、該中心Ｏの下方８ｍｍで終わる。従って、累進帯長（中間部の長さ）は１９ｍｍである。
【００７９】
主として近方視に特化させた累進屈折力レンズ２０を基準とする一連の累進屈折力レンズシリーズに属する累進屈折力レンズであれば、幅Ｗ_ｄｔと幅Ｗ_ｎｔの比が条件（１２）を満たす。
【００８０】
【数３６】

【００８１】
遠用部の明視域幅と近用部の明視域幅との関係が、条件（１２）を満たすように設計された累進屈折力レンズは、透過性能が高い近用累進屈折力レンズである。そして該累進屈折力レンズを装用する者は、特に卓上等の近距離にある物体を観察するときに優れた装用感を得ることができる。
【００８２】
図１５は累進屈折力レンズ２０を基準設計とする一連の累進屈折力レンズシリーズに属するいくつかの累進屈折力レンズに関する、透過非点収差分布と透過平均屈折力分布の一覧である。図１５に示す各累進屈折力レンズは、遠用部球面屈折力Ｓｐｈが一定で、ベースカーブがそれぞれ異なっている。具体的には、各累進屈折力レンズは、遠用部球面屈折力Ｓｐｈが−２．０ディオプター、加入度数ＡＤが２．０ディオプターであり、ベースカーブＢＣを図中の上から２．４３、３．２１、４．１６、４．７８（単位は全てディオプター）と変化させている。なお、各累進屈折力レンズは、上記累進屈折力レンズ２０と同様に、累進帯がレンズ幾何学中心Ｏの上方１１ｍｍから加入が始まり、下方８ｍｍで終わるように設計されている。図１６は、上記Ｗ_ｄｔ／Ｗ_ｎｔがベースカーブの変化に対しどのように変化するかを示したグラフである。図１５に示す収差図および図１６に示すグラフから分かるように、遠用部球面屈折力とベースカーブのいずれか一方または両方が変化しても透過非点収差はほぼ同一の分布傾向を示しており、高い光学性能を実現していることがわかる。なお、図１６より、累進屈折力レンズ２０を基準設計とする一連の累進屈折力レンズシリーズに属するレンズは、条件（１２）を満たすことがわかる。
【００８３】
図１７は実施形態の累進屈折力レンズ１０に対する比較例としての累進屈折力レンズ３０の透過性能での非点収差分布（図１７Ａ）と平均屈折力分布（図１７Ｂ）である。また図１８は、比較例としての累進屈折力レンズ３０の面性能での非点収差分布（図１８Ａ）と平均屈折力分布（図１８Ｂ）である。
【００８４】
累進屈折力レンズ３０は、累進屈折力レンズ１０と同様に、遠用部球面屈折力Ｓｐｈが０．０ディオプター、加入度数ＡＤが２．０ディオプター、ベースカーブＢＣが３．２１ディオプターである。累進帯はレンズ幾何学中心Ｏの上方１１ｍｍから加入が始まり、下方８ｍｍで終わる。図１５や図１６に示す比較例では、透過性能評価の最適化を行わず、面性能評価で非点収差を調整している。図１７と図１８を比べると分かるように、透過と面での性能は大きく異なっており、特にレンズの幾何学中心付近以外で顕著である。そのため比較例では、装用状態において遠用部、近用部とも明視域幅が狭く、使用者にとって広い視野を実現出来ていない。それに対し図１に示す累進屈折力レンズ１０の透過収差分布では、遠用部、近用部とも明視域幅が広く、高い光学性能を実現している。
【００８５】
以上が本発明の実施形態である。外観性能と光学性能を両立した累進屈折力レンズ系列を実現するには、透過収差が最適化されていて、かつベースカーブ、球面度数が変化しても、透過収差分布はほとんど変化しないことが必要である。この点、本願発明によれば、面非点収差と透過非点収差の明視域の幅をある一定の条件を持ってコントロールすることにより達成している。
【００８６】
【発明の効果】
以上のように、本発明の累進屈折力レンズ系列および累進屈折力レンズによれば、装用者の実質的な視野である明視域を広く確保し、かつ眼鏡の美的外観を良好に保つためにベースカーブ、遠用部球面屈折力を変化させた場合であっても収差バランスが略統一された累進屈折力レンズを提供することができる。
【図面の簡単な説明】
【図１】本発明の第１実施形態の累進屈折力レンズの透過性能での非点収差分布と平均屈折力分布を表す。
【図２】本発明の第１実施形態における累進屈折力レンズの面性能での非点収差分布と平均屈折力分布を表す。
【図３】実施形態の累進屈折力レンズにおける透過性能の特徴量を説明する図である。
【図４】実施形態の累進屈折力レンズにおける面性能の特徴量を説明する図である。
【図５】第１実施形態の累進屈折力レンズを基準設計とする一連の累進屈折力レンズシリーズに属するいくつかの累進屈折力レンズに関する、透過非点収差分布と透過平均屈折力分布、および面非点収差分布と面平均屈折力分布の一覧である。
【図６】遠用部球面屈折力Ｓｐｈがプラス範囲に設定されたときに、（Ｗ_ｄｓ／Ｗ_ｎｓ）／（Ｗ_ｄｔ／Ｗ_ｎｔ）がベースカーブの変化に対しどのように変化するかを示すグラフである。
【図７】遠用部球面屈折力Ｓｐｈがプラス範囲に設定されたときに、上記Ｗ_ｄｓ／Ｗ_ｎｓがベースカーブの変化に対しどのように変化するかを示すグラフである。
【図８】第１実施形態の累進屈折力レンズを基準設計とする一連の累進屈折力レンズシリーズに属するいくつかの累進屈折力レンズに関する、透過非点収差分布と透過平均屈折力分布、および面非点収差分布と面平均屈折力分布の一覧である。
【図９】遠用部球面屈折力Ｓｐｈがマイナス範囲に設定されたときに、上記（Ｗ_ｄｓ／Ｗ_ｎｓ）／（Ｗ_ｄｔ／Ｗ_ｎｔ）がベースカーブの変化に対しどのように変化するかを示すグラフである
【図１０】遠用部球面屈折力Ｓｐｈがマイナス範囲に設定されたときに、上記Ｗ_ｄｓ／Ｗ_ｎｓがベースカーブの変化に対しどのように変化するかを示すグラフである。
【図１１】第１実施形態の累進屈折力レンズを基準設計とする一連の累進屈折力レンズシリーズに属するいくつかの累進屈折力レンズに関する、透過非点収差分布と透過平均屈折力分布、および面非点収差分布と面平均屈折力分布の一覧である。
【図１２】遠用球面屈折力Ｓｐｈを一定としてＷ_ｄｔ／Ｗ_ｎｔがベースカーブの変化に対しどのように変化するかを示すグラフである。
【図１３】第２実施形態の累進屈折力レンズの透過性能での非点収差分布と平均屈折力分布を表す。
【図１４】本発明の第２実施形態における累進屈折力レンズの面性能での非点収差分布と平均屈折力分布を表す。
【図１５】本発明の第２実施形態の累進屈折力レンズを基準設計とする一連の累進屈折力レンズシリーズに属するいくつかの累進屈折力レンズに関する、透過非点収差分布と透過平均屈折力分布の一覧である。
【図１６】遠用球面屈折力Ｓｐｈを一定としてＷ_ｄｔ／Ｗ_ｎｔがベースカーブの変化に対しどのように変化するかを示したグラフである。
【図１７】本発明の第１実施形態の累進屈折力レンズに対する比較例である。
【図１８】本発明の第１実施形態の累進屈折力レンズに対する比較例である。
【符号の説明】
１０ 累進屈折力レンズ
２０ 累進屈折力レンズ
３０ 累進屈折力レンズ（比較例）
Ｏ 幾何学中心
Ｘ レンズの上下方向を分ける基準線
Ｙ レンズの左右方向を分ける基準線
ＤＬ レンズの幾何学中心から基準線Ｙに沿って上方の遠用部幅Ｗ_ｄｔおよびＷ_ｄｓを規定する位置までの長さ
ＮＬ レンズの幾何学中心から基準線Ｙに沿って下方の近用部幅Ｗ_ｎｔおよびＷ_ｎｓを規定する位置までの長さ
ＧＬ 主注視線
Ｗ_ｄｓ 遠用部において、面非点収差がレンズの加入度数ＡＤの１／２となる領域の水平方向の幅
Ｗ_ｎｓ 近用部において、面非点収差がレンズの加入度数ＡＤの１／２となる領域の水平方向の幅
Ｗ_ｄｔ 遠用部において、レンズを透過した光線における非点収差がレンズの加入度数ＡＤの１／２となる領域の水平方向の幅
Ｗ_ｎｔ 近用部において、レンズを透過した光線における非点収差がレンズの加入度数ＡＤの１／２となる領域の水平方向の幅[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a progressive-power lens for the purpose of correcting presbyopia.
[0002]
[Prior art]
In designing and evaluating a progressive-power lens that corrects presbyopia, the entire lens is often divided into three regions. That is, there are three areas: an area for viewing a distant object called a distance part, an area for viewing an intermediate distance called an intermediate part, and an area for viewing a near area called a near part. In particular, the intermediate portion is a portion where the refractive power of the lens continuously changes, and is also called a progressive zone.
In general, in a progressive-power lens, object distances corresponding to the three regions are not clearly defined. Therefore, in this specification, for convenience of explanation, the distance portion, the intermediate portion, and the near portion are for observing an object that is relatively far away, an object that is in the middle, and an object that is near in the progressive-power lens. Means the area of
[0003]
Usually, in a progressive-power lens, the positions for measuring the vertex refractive power in the distance portion and the near portion are referred to as the distance portion measurement reference point and the near portion measurement reference point, respectively. In general, the distance measurement reference point and the near measurement reference point are often displayed as circular or elliptical areas on the lens. However, in this specification, for convenience of explanation, the distance measurement reference point and the near measurement reference point are regarded as points, specifically, the midpoint of a circular or elliptical figure shown on the lens. Means.
[0004]
In the present invention, the locus of the point where the line of sight and the lens surface intersect when the eye is rotated in the vertical direction is called the main gazing line. The main line of sight is a curve that passes through the distance measurement reference point, the intermediate portion, and the near measurement reference point. In general, when observing an object in the vicinity, the distance between the pupils is shorter than when observing an object in the distance. The main gazing line is deviated from the reference line to the nose side in the downward direction from the vicinity of the center of the lens. Here, the reference line refers to a vertical line extending in the vertical direction through the center of the distance portion of the lens. In the present specification, expressions indicating directions such as upward, downward, horizontal, and vertical indicate directions based on the state of the spectacle lens during wearing.
[0005]
In the design of a progressive-power lens, it is almost impossible to ensure a clear and bright area uniformly from the distance portion to the near portion. In addition, The clear vision region refers to a region where an object can be seen without feeling image distortion or blur, and generally the region where astigmatism is 0.5D or 1.0D or less. Generally, the horizontal width of the intermediate clear vision region where the refractive power continuously changes tends to be narrower than the widths of the other two regions. Accordingly, the progressive-power lens is classified into several types depending on which region the width of the clear vision region is designed to be wide.
[0006]
A progressive-power lens having a wide clear vision area width in the distance portion and near-distance portion as much as possible and a narrow intermediate portion clear vision region width is a so-called general-purpose progressive lens, and a far-distance lens is applicable. The general-purpose progressive type lens has a so-called image distortion caused by aberrations in the middle part, particularly in the middle part when the eye wearer moves his / her head up and down or left and right at a relatively high speed. There is a problem in that it may be perceived as “shaking” and may cause a strong discomfort to the wearer. In order to avoid this problem, it is necessary to reduce astigmatism around the intermediate portion.
[0007]
So, in the middle Clear vision A progressive power lens of a medium-to-neighbor type that secures a wider area above the general-purpose progressive lens is proposed. The progressive addition lens for middle and near-end uses a progressive zone (intermediate part) that extends upward to reduce the rate of change of refractive power in the vertical direction of the lens, thereby suppressing aberrations on the side of the intermediate part and wide. An intermediate clear vision area is secured. Therefore, the progressive addition lens for the middle and near ends results in the distance portion. Clear vision area However, the above-described shaking is small, and the lens has excellent performance for indoor use mainly in intermediate vision and near vision.
[0008]
Further, a progressive progressive lens of near-progressive type has also been proposed. In the near progressive lens, the clear vision area above the middle portion and the far vision portion is narrowed to ensure a wide clear vision area width below the middle portion and near portion. Therefore, the lens is excellent in use particularly when working at a distance close to the hand. In the present specification, the distance portion of the near progressive lens means a region that is relatively distant, and is actually a region for observing an object about 1 to 2 m away.
[0009]
In the design and evaluation of a conventional progressive-power lens, the optical performance on the progressive-power surface (hereinafter referred to as surface performance) has been the subject. In other words, the power error and astigmatism representing the optical performance of the lens have been calculated based on the average and difference between the maximum principal curvature and the minimum principal curvature of the progressive refractive surface, respectively. In addition, the type of progressive lenses such as the above-mentioned bifocal, middle-near bifocal, and near-progressive progressive types have been substantially determined by the aberration arrangement of the surface.
[0010]
However, a spectacle lens suitable for a wearer originally has optical performance (hereinafter referred to as transmission performance) evaluated based on a light beam that has passed through an arbitrary point of the lens in a state where the progressive lens is actually worn. It is desirable that it is good for the person. Here, the surface performance and transmission performance of the spectacle lens are as follows: In general Is different. This difference appears particularly in the peripheral portion of the lens. Incidentally, the transmission performance of spectacle lenses, particularly progressive power lenses, and the evaluation method of the transmission performance are described in detail in Japanese Patent Application Laid-Open No. 11-125580 relating to the application of the present applicant.
[0011]
Furthermore, a spectacle lens that realizes a comfortable spectacle wearing environment is also required to have a good appearance when worn, that is, to have an excellent aesthetic appearance. In general, a thin spectacle lens is more preferable not only in appearance but also in terms of manufacturing restrictions. And since glasses are composed of a pair of left and right lenses and a frame, the problem regarding the aesthetic appearance cannot be considered without balancing the left and right lenses.
[0012]
Here, when the required refractive powers of the left and right progressive addition lenses are equal, the shape of the spectacle lens matches both the outer surface (object side surface) and the inner surface (the surface closer to the wearer's eyes). On the other hand, if the difference in refractive power required for the left and right progressive-power lenses becomes large, the left and right progressive-power lenses have different shapes when they are designed separately, and the left and right are unbalanced. This detracts from the aesthetic appearance of the glasses. The superiority or inferiority of the aesthetic appearance of the glasses is generally largely due to the outer shape. Therefore, in order to provide eyeglasses with an excellent aesthetic appearance, it is desirable to align the outer surface shapes of the left and right lenses.
[0013]
However, in general, the shape that minimizes the aberration with respect to the required refractive power is limited, so focusing on the shape alone and simply matching the base curve to one side increases the aberration and degrades the optical performance. Resulting in. That is, it is necessary to design a progressive lens in consideration of the balance between shape and optical performance. Therefore, conventionally, only one type of lens having a specific base curve is designed for a specific refractive power.
[0014]
In view of the requirements for the progressive power lens, conventionally, progressive power lenses and lens manufacturing methods exemplified in the following Patent Documents 1 to 4 have been proposed.
[0015]
[Patent Document 1]
JP-A-9-90291
[Patent Document 2]
JP 2001-318344 A
[Patent Document 3]
JP 2001-318345 A
[Patent Document 4]
JP 2002-122824 A
[0016]
The progressive power lens of Patent Document 1 improves the transmission performance by repeating the design by trial and error after performing basic design by surface performance evaluation. However, although a guideline is described to some extent regarding the lens design for improving the power distribution, there is no mention of a guideline for improving astigmatism that most affects the performance of the lens. It is difficult to say that the transmission aberration distribution map obtained as a result ensures a sufficiently wide clear vision region.
[0017]
The progressive-power lenses of Patent Document 2 and Patent Document 3 described above are designed to have the same optical specifications for transmitted light when the base curve changes according to the distance-part spherical power required by the wearer. It belongs to the progressive power lens series aimed at. However, the main purpose is to improve the performance in the distance portion and to unify the series of progressive power lenses, and there is no specific mention of a method for improving the astigmatism distribution of the entire lens. Also, in order to improve the aesthetic appearance of the glasses, it is not considered at all to align the base curves of the left and right lenses.
[0018]
The lens manufacturing method of Patent Document 4 makes it possible to realize a progressive-power lens having a certain distance portion spherical refractive power with a plurality of base curves. Then, when the same base curve is used for the left and right lenses having different frequencies, this is a manufacturing method that minimizes the deterioration of the optical performance of each lens. However, the optimization is simply performed by simply suppressing the aberration for each lens, and the transmission aberration distribution among the plurality of base curves is not intended to be the same.
[0019]
Advantages of unifying the lens transmission aberration distribution with respect to changes in the base curve and the distance portion spherical power include the following points. First, when the spherical power is different between the left and right, even if the base curve is the same in order to keep the appearance in the state of wearing glasses, a natural field of view can be secured without changing the appearance of the left and right lenses. . Furthermore, if the transmission aberration distribution is substantially the same even when the spherical power changes, the base curve adjustment as described above can be performed in a wider range, and the range of selection by the user can be expanded. In the prior art, there is no example that realizes a progressive power lens series in which aberration balance is unified with respect to changes in both base curve and spherical power.
[0020]
[Problems to be solved by the invention]
In view of the circumstances as described above, the present invention provides a progressive power lens having a substantially wide field of view by satisfactorily suppressing astigmatism in transmission performance, and further, spherical refraction at the distance portion of the left and right lenses. To provide a progressive-power lens belonging to a series of progressive-power lenses that maintains a good appearance even when the force is different, and also has a uniform aberration distribution even if the spherical power and distance of the base portion change. It is.
[0021]
[Means for Solving the Problems]
In order to achieve the above object, a progressive-power lens according to the present invention has the following configuration. That is, at least one surface of the lens has a distance portion having a refractive power for viewing a distance, a near portion having a refractive power for viewing a near distance, and the distance portion having a refractive power that gradually changes. And a progressive surface comprising an intermediate portion for continuously connecting the refractive power of the near portion, Based on a lens with a predetermined optical performance Designed, multiple type In the progressive-power lens belonging to a series of progressive-power lenses having a base curve, the base curve of the first lens arbitrarily extracted from the series is represented by BC ₁ , The base curve of the second lens is BC ₂ (However, BC ₁ <BC ₂ When the spherical refractive power Sph (unit: diopter) of the distance portion of the first lens and the second lens is +1 or more, the following condition (1) is satisfied, and the spherical refractive power Sph is −1: The following condition (2) is satisfied when:
[0022]
[Formula 13]

[Expression 14]

[0023]
However, in the above conditions (1) and (2), when the addition power that is the difference between the refractive power of the distance portion and the refractive power of the near portion is AD (unit: diopter), W _dt Represents the horizontal width of the region where the transmission astigmatism is AD / 2 at a height away from the geometric center in the distance portion by a predetermined distance. W _nt Represents the horizontal width of the region where the transmission astigmatism is AD / 2 at a height that is a predetermined distance downward from the geometric center in the near portion. W _ds Represents the width of the region where the surface astigmatism is AD / 2 at a height away from the geometric center in the distance portion by a predetermined distance. W _ns Represents the width of the region where the surface astigmatism is AD / 2 at a height that is a predetermined distance downward from the geometric center in the near portion. The same applies to each condition shown in the following text.
[0024]
In this way, by determining the relationship between surface astigmatism and transmission astigmatism in the distance portion and near-distance portion, the transmission astigmatism can be kept low, and the clear visual field that is a substantial field of view of the wearer is widened. Can be secured. In addition, in order to keep the aesthetic appearance of the glasses good, multiple types of base curves are prepared for the power of a specific distance portion, and a progressive power lens series with a unified aberration balance in transmission performance The progressive-power lens for comprising can be provided. According to the progressive-power lens belonging to this lens series, by matching the aberration balance of the left and right lenses substantially, the eyeglasses that have substantially the same appearance through the left lens and the right lens can be obtained. Provided. Note that none of Patent Documents 1 to 4 mentions the above quantitative relationship between astigmatism surface evaluation and transmission evaluation, which is an important performance in spectacle lenses. Therefore, it is impossible to realize a progressive power lens series in which the balance of transmission astigmatism is unified as in the present invention based on any document.
[0025]
The basic specifications of the lens include the distance portion spherical refractive power Sph (unit: diopter), the addition power AD (unit: diopter) which is the difference between the distance portion refractive power and the near portion refractive power, progressive The band length L (unit: millimeter) is exemplified.
[0026]
The progressive-power lens satisfies the following condition (3) when the spherical refractive power Sph (unit: diopter) is +1 or more, and further satisfies the following condition when the spherical refractive power Sph is −1 or less. (4) can be satisfied.
[0027]
[Expression 15]

[Expression 16]

[0028]
If the base curve is relatively shallow, Surface astigmatism and transmission astigmatism Is Satisfy the above conditions (3) and (4) When Suitable Is .
[0029]
From another point of view, the progressive-power lens according to the present invention is such that at least one surface of the lens has a distance portion having a refractive power for viewing the distance, and a near-use lens having a refractive power for viewing the near. And a progressive surface comprising an intermediate portion for continuously connecting the refractive power of the distance portion and the near portion, the refractive power of which gradually changes, Based on a lens with a predetermined optical performance Designed, multiple type In the progressive-power lens belonging to a series of progressive-power lenses having a base curve, the base curve of the first lens arbitrarily extracted from the series is represented by BC ₁ , The base curve of the second lens is BC ₂ (However, BC ₁ <BC ₂ When the spherical refractive power Sph (unit: diopter) of the distance portion of the first lens and the second lens is +1 or more, the following condition (5) is satisfied, and the spherical refractive power Sph is −1: The following condition (6) is satisfied when:
[0030]
[Expression 17]

[Formula 18]

[0031]
In this way, by determining the arrangement of the surface astigmatism in the distance portion and the near portion, the astigmatism in the transmission performance can be kept low, and a clear vision region that is a substantial visual field of the wearer is ensured widely. be able to. In addition, in order to keep the aesthetic appearance of the eyeglasses in a good condition, multiple types of base curves are prepared for specific distance-use power, and a progressive power lens series with a unified aberration balance in transmission performance The progressive-power lens for comprising can be provided.
[0032]
From another point of view, the progressive-power lens of the present invention is such that at least one surface of the lens has a distance portion having a refractive power for viewing far, a near portion having a refractive power for viewing near, And a progressive surface comprising an intermediate portion that gradually changes the refractive power and continuously connects the refractive power of the distance portion and the near portion, Based on a lens with a predetermined optical performance Designed, multiple type In the progressive-power lens belonging to a series of progressive-power lenses having a base curve, the base curve of the first lens arbitrarily extracted from the series is represented by BC ₁ , The spherical refractive power of the distance portion of the first lens is Sph ₁ (Unit: diopter), the base curve of the second lens is BC ₂ , The spherical refractive power of the distance portion of the second lens is Sph ₂ (Unit: Diopter) BC ₁ ≠ BC ₂ Or Sph ₁ ≠ Sph ₂ The following condition (7) is satisfied.
[0033]
[Equation 19]

[0034]
As in condition (7), by determining the distribution of transmission astigmatism in the distance portion and the near portion, the transmission astigmatism can be kept low, and the clear visual field that is the substantial visual field of the wearer is widened. Can be secured. In addition, the progressive power lens series has a unified aberration balance even when the base curve is changed to keep the appearance of the glasses good, or the distance spherical power is changed according to the specifications. A progressive power lens is provided.
[0035]
In the above condition (7), the spherical refractive power Sph of the distance portion of the first lens ₁ And spherical power Sph of the distance part of the second lens ₂ With the same value Sph _f The progressive power lens satisfies the following condition (8).
[0036]
[Expression 20]

[0037]
Further, in the progressive-power lens satisfying the condition (8), the above Sph _f When taking a value smaller than 0, the following condition (9) is also satisfied.
[0038]
[Expression 21]

[0039]
In the above condition (7), the base curve BC of the first lens ₁ And second lens base curve BC ₂ Both have the same value BC _f The progressive power lens satisfies the following condition (10).
[0040]
[Expression 22]

[0041]
In each of the progressive-power lenses described above, it is desirable that the length of the intermediate portion, that is, the progressive zone length is 15 mm or more and 30 mm or less. By setting the progressive zone length as long as 15 mm or more, it is possible to increase the width of the intermediate clear vision zone and to suppress the occurrence of astigmatism on the side of the progressive zone, that is, the left and right regions of the lens. Become. Further, by setting the progressive zone length to 30 mm or less, the rotation angle of the eyes when moving the line of sight from a distant place to a close place is reduced, and the burden on the eyes of the user can be reduced. As a result, it is possible to provide a progressive-power lens that is less swayed and distorted and is less tiring even when used for a long time.
[0042]
In each of the progressive power lenses described above, it is desirable that the lens inner surface be a progressive surface. The inner surface of the lens means a surface on the eye side of the spectacle wearer. By making the progressive surface the inner surface, the outer surface only needs to be spherically processed. This eliminates the need to prepare a large number of outer surface molds for each difference in addition refractive power and progressive zone length, thereby reducing the manufacturing burden and greatly reducing the manufacturing cost.
[0043]
Here, the position away from the geometric center in the distance portion substantially coincides with the distance measurement reference point, and the position away from the geometric center in the near portion is the near measurement point. Can be substantially matched. The predetermined distance is preferably 15 mm.
[0044]
The progressive-power lens according to the present invention has the following configuration. That is, at least one surface of the lens has a distance portion having a refractive power for viewing a distance, a near portion having a refractive power for viewing a near portion, and a distance portion having a refractive power that gradually changes. In a progressive-power lens that is a progressive surface having an intermediate portion that continuously connects the refractive power of the near portion, the addition power that is the difference between the refractive power of the distance portion and the refractive power of the near portion is expressed as AD (unit: Diopter), width W _dt And width W _nt Is designed to satisfy the following condition (11).
[0045]
[Expression 23]

[0046]
In this way, by determining the transmission astigmatism distribution in the distance portion and the near portion, the transmission astigmatism is suppressed to a low level, and a clear visual field that is a substantial field of view of the wearer is secured. It is possible to realize a mid- and progressive-power lens that provides excellent wearing feeling when working indoors or on a table.
[0047]
If you want to manufacture a medium-to-neighbor progressive power lens or a near-term progressive power lens with an emphasis on the observation of objects in the vicinity, design to meet the following condition (12) and It is preferable to increase the area.
[0048]
[Expression 24]

[0049]
Also in the progressive-power lens satisfying the above conditions (11) and (12), it is desirable that the length of the intermediate portion, that is, the progressive zone length is 15 mm or more and 30 mm or less. By setting the progressive zone length as long as 15 mm or more, it is possible to increase the width of the intermediate clear vision zone and to suppress the occurrence of astigmatism on the side of the progressive zone, that is, the left and right regions of the lens. Become. Further, by setting the progressive zone length to 30 mm or less, the rotation angle of the eyes when moving the line of sight from a distant place to a close place is reduced, and the burden on the eyes of the user can be reduced. As a result, it is possible to provide a progressive-power lens that has little distortion and is not fatigued even after long-term use. Also in the progressive-power lens, it is desirable that the inner surface of the lens is a progressive surface because of the ease of processing the lens.
[0050]
DETAILED DESCRIPTION OF THE INVENTION
[0051]
FIG. 1 shows an astigmatism distribution (FIG. 1A) and an average refractive power distribution (FIG. 1B) in the transmission performance of the progressive addition lens 10 according to the first embodiment of the present invention. The intervals between the contour lines in the figure are displayed every 0.5 diopters, and the same applies to the distribution charts shown below. In the following description, it is assumed that the progressive-power lens 10 has a diameter of 60 mm. FIG. 2 shows an astigmatism distribution (FIG. 2A) and an average refractive power distribution (FIG. 2B) in the surface performance of the progressive-power lens 10 shown in FIG. The transmission astigmatism distribution shown in FIG. 1A is a target value of the optical performance of lenses belonging to a series of progressive power lens series in the entire processing region of the progressive power lens 10 and the base curve at all points. That is, the progressive-power lens 10 is a lens designed as a reference in a series of progressive-power lenses.
[0052]
The progressive-power lens 10 serving as the reference design of the first embodiment is a so-called medium lens in which the distance portion spherical refractive power Sph is 0.0 diopter, the addition power AD is 2.0 diopter, and the base curve BC is 3.21 diopter. This is a near progressive power lens. The progression zone starts from 11 mm above the lens geometric center O and ends at 8 mm below the center O. Therefore, the progressive zone length (intermediate length) is 19 mm.
[0053]
FIG. 3 is a diagram for explaining the characteristic amount of the transmission performance in the progressive-power lens 10. FIG. 4 is a diagram for explaining the feature amount of the surface performance in the progressive-power lens 10. 3 and 4, the left and right reference lines X and the upper and lower reference lines Y pass through the geometric center O and extend in directions orthogonal to each other. The extending direction of the left and right reference lines X is substantially coincident with the horizontal direction, and the extending direction of the upper and lower reference lines Y is substantially coincident with the vertical direction. Further, the main gaze line GL is deviated to the nose side from the intermediate part to the near part.
[0054]
Two curves ALt shown in FIG. 3 represent contour lines in which the transmission astigmatism is ½ of the addition power AD. In the progressive-power lens 10, W _dt (Unit: mm) represents the horizontal width between two curves ALt at a height DL (unit: mm) above the horizontal reference line X including the geometric center O in the vertical direction. W _nt (Unit: mm) represents a horizontal width between two curves ALt at a height NL (unit: mm) in the vertical direction from the left and right reference line X. In the progressive-power lens 10, the area between the two curves ALt is defined as a clear vision area.
[0055]
Two curves ALs shown in FIG. 4 represent contour lines in which the surface astigmatism is ½ of the addition power AD. W _ds (Unit: mm) represents the horizontal width between the two curves ALs at a height above the geometric center O along the vertical reference line Y by DL. W _ns (Unit: mm) represents the horizontal width between two curves ALs at a height NL below the geometric center O along the vertical reference line Y.
[0056]
In the progressive-power lens 10, DL is set to be approximately equal to the distance from the left / right reference line X to the distance power measurement point on the main gazing line. Further, NL is set to be approximately equal to the distance from the left / right reference line X to the near power measurement point on the main gazing line. Therefore, in the present embodiment, the DL and NL are each set to 15 mm. Therefore, Wdt and Wds are two curves in the distance portion. ALt or It means the horizontal width between ALs, Wnt and Wns are two curves in the near part ALt or It means the horizontal width between ALs.
[0057]
When DL and NL are each set to 15 mm, in the transmission astigmatism distribution and the surface astigmatism distribution of the progressive addition lens 10, the region width (W where the astigmatism is ½ of the addition power AD) _dt , W _nt , W _ds , W _ns ), The following features are derived.
[0058]
Specifically, it is assumed that two lenses (first lens and second lens) are arbitrarily extracted from a series of progressive-power lenses with the progressive-power lens 10 as a reference design. And the W of these two lenses _nt And W _dt Ratio, and W _ds And W _ns Each ratio is obtained. Next, when both the first lens and the second lens have a specific distance portion spherical refractive power Sph and the base curve of each lens changes, W _nt And W _dt Ratio and W _ds And W _ns Examine the relationship of the ratios. Then, the following condition (1) is satisfied when the distance portion spherical refractive power Sph is +1 or more, and the following condition (2) is satisfied when the spherical refractive power Sph is −1 or less.
[0059]
[Expression 25]

[Equation 26]

However, BC ₁ Represents the base curve of the first lens, BC ₂ Represents the base curve of the second lens. And BC ₁ <BC ₂ It is.
[0060]
Furthermore, if a relatively shallow base curve is selected to make the lens thinner, W _nt And W _dt Ratio and W _ds And W _ns When the distance portion spherical refractive power Sph is larger than +1 diopter, the following condition (3) is satisfied, and when the spherical refractive power is smaller than −1 diopter, the following condition (4) is satisfied. Fulfill.
[0061]
[Expression 27]

[Expression 28]

[0062]
Further, attention is paid only to the surface performance of the first lens and the second lens arbitrarily extracted from the series of progressive power lens series. The W of each lens when the first lens and the second lens both have a specific distance spherical refractive power and the base curve of each lens changes. _ds And W _ns Examine the ratio. Then, when the distance spherical power Sph of the first lens and the second lens is +1 or more, the following condition (5) is satisfied. Further, when the spherical refractive power Sph is −1 or less, the following condition (6) is satisfied.
[0063]
[Expression 29]

[30]

However, BC ₁ <BC ₂ It is.
[0064]
By performing the surface design of the first lens and the second lens so that the conditions (5) and (6) are satisfied, the aberration balance is unified as a whole without deteriorating the aesthetic appearance while enhancing the transmission performance. A spectacle lens is provided.
[0065]
In addition, paying attention only to the transmission performance of the first lens and the second lens arbitrarily extracted from the series of progressive power lens series, _dt And W _nt Examine the ratio. Then, when either the base curve or the distance portion spherical refractive power in both the first lens and the second lens changes, the condition (7) is satisfied. Both the first lens and the second lens have a specific distance spherical power Sph _f When the base curve of each lens changes, the condition (8) is satisfied. When the condition (8) is satisfied, the distance spherical power Sph _f Is negative, the first lens and the second lens further satisfy the condition (9). Both the first lens and the second lens have a specific base curve BC _f If the distance spherical refractive power of each lens changes, the condition (10) is satisfied.
[0066]
[31]

[Expression 32]

[Expression 33]

[Expression 34]

[0067]
By designing the transmission performance of the first lens and the second lens so as to satisfy any one of the above conditions (8) to (10) with respect to changes in the base curve and the distance spherical power, Control the viewing zone width according to the specs of the glasses. As a result, it is possible to realize a progressive-power lens having good optical performance in the wearing state and excellent in aesthetic appearance.
[0068]
When attention is paid to a progressive-power lens unit (for example, progressive-power lens 10) belonging to a series of progressive-power lenses, the width W in the transmission performance of the lens _dt And width W _nt The ratio satisfies the condition (11).
[0069]
[Expression 35]

[0070]
The progressive addition lens designed so that the relation between the clear vision area width of the distance portion and the clear vision area width of the near portion satisfies the condition (11) is a progressive power lens for middle and near areas having high transmission performance. It is. A person who wears the progressive-power lens can obtain an excellent wearing feeling particularly when working indoors or on a table.
[0071]
FIG. 5 shows the transmission astigmatism distribution, the transmission average refractive power distribution, and the surface astigmatism distribution regarding several progressive power lenses belonging to a series of progressive power lenses having the progressive power lens 10 as a reference design. And a list of surface average refractive power distributions. Each progressive-power lens shown in FIG. 5 has a common distance spherical power Sph of +2.00 diopters, an add power AD of 2.0 diopters, and a base curve BC from the top in the figure. 2.43, 3.21, 4.16, 4.78, 5.69, 6.48 (units are all diopters). FIG. 6 shows the above (W) when the distance portion spherical refractive power Sph is set in the plus range. _ds / W _ns ) / (W _dt / W _nt ) Is a graph showing how the curve changes with respect to the change in the base curve. FIG. 7 shows the above-mentioned W when the distance portion spherical refractive power Sph is set in the plus range. _ds / W _ns It is a graph which shows how changes with respect to the change of a base curve. As can be seen from the aberration diagrams and graphs shown in FIGS. 5 to 7, the transmission astigmatism shows almost the same distribution tendency even when the base curve changes. In addition, every progressive-power lens has almost the same aberration distribution as the progressive-power lens 10, and thus has high optical performance.
[0072]
It can be seen from FIG. 6 that lenses belonging to a series of progressive-power lenses having the progressive-power lens 10 as a reference design satisfy the condition (1). The lens also satisfies the condition (3) Yes. Further, from FIG. 7, the lenses belonging to a series of progressive power lenses having the progressive power lens 10 as a reference design are as follows: In the case of Sph + 4.00, It can be seen that the condition (5) is also satisfied.
[0073]
FIG. 8 shows a transmission astigmatism distribution, a transmission average refractive power distribution, and a surface astigmatism distribution regarding several progressive power lenses belonging to a series of progressive power lenses having the progressive power lens 10 as a reference design. And a list of surface average refractive power distributions. Each progressive-power lens shown in FIG. 8 has a common distance spherical power Sph of -2.00 diopters, an add power AD of 2.0 diopters, and a base curve BC in the upper part of the figure. To 1.62, 2.43, 3.21, 4.16, 4.78, 5.69 (units are all diopters). FIG. 9 shows the above (W) when the distance portion spherical refractive power Sph is set in the minus range. _ds / W _ns ) / (W _dt / W _nt ) Is a graph showing how the curve changes with respect to the change in the base curve. FIG. 10 shows the above-mentioned W when the distance portion spherical refractive power Sph is set in the minus range. _ds / W _ns It is a graph which shows how changes with respect to the change of a base curve. As can be seen from the aberration diagrams and graphs shown in FIGS. 8 to 10, even when the base curve changes, the transmission astigmatism shows almost the same distribution tendency. In addition, every progressive-power lens has almost the same aberration distribution as the progressive-power lens 10, and thus has high optical performance.
[0074]
From FIG. 9, it can be seen that lenses belonging to a series of progressive-power lenses having the progressive-power lens 10 as a reference design satisfy the condition (2). . S ph -2.00 , -4.00 When set to, no matter which lens is extracted arbitrarily, (4) You can see that Further, from FIG. 10, lenses belonging to a series of progressive power lenses having the progressive power lens 10 as a reference design are as follows: In Sph-2.00, -4.00 It can be seen that the condition (6) is also satisfied.
[0075]
FIG. 11 shows the transmission astigmatism distribution, the transmission average refractive power distribution, and the surface astigmatism distribution regarding several progressive addition lenses belonging to a series of progressive addition lenses having the progressive addition lens 10 as a reference design. It is a list of surface average refractive power distribution. Each progressive-power lens shown in FIG. 11 has a common base curve of 4.16 diopters, an addition power AD of 2.0 diopters, and a distance portion spherical power of −4 from the top in the figure. .00, -2.00, 0.00, +2.00, +4.00 (units are all diopters). FIG. 12 shows the above W _dt / W _nt It is a graph which shows how changes with respect to the change of a base curve. As can be seen from the aberration diagram shown in FIG. 11 and the graph shown in FIG. 12, the transmission astigmatism shows almost the same distribution tendency even if the distance portion spherical refractive power changes or the base curve changes. ing. In addition, every progressive-power lens has almost the same aberration distribution as the progressive-power lens 10, and thus has high optical performance.
[0076]
From the graph shown in FIG. 12, it can be seen that lenses belonging to a series of progressive-power lenses having the progressive-power lens 10 as a reference design satisfy the conditions (7) to (11).
[0077]
FIG. 13 shows an astigmatism distribution (FIG. 13A) and an average refractive power distribution (FIG. 13B) in the transmission performance of the progressive addition lens 20 in the second embodiment of the present invention. The intervals between the contour lines in the figure are displayed every 0.5 diopters, and the same applies to the distribution charts shown below. In the following description, it is assumed that the progressive power lens 20 has a diameter of 60 mm. FIG. 14 shows an astigmatism distribution (FIG. 14A) and an average refractive power distribution (FIG. 14B) in the surface performance of the progressive addition lens 20 shown in FIG. The transmission astigmatism distribution shown in FIG. 13A is a target value of the optical performance of a lens belonging to a series of progressive power lens series in the entire processing region of the progressive power lens 20 and the base curve at all points. That is, the progressive addition lens 20 is a lens designed as a reference in a series of progressive addition lens series.
[0078]
The progressive-power lens 20 that is the standard design of the second embodiment is a so-called near-use lens in which the distance portion spherical power Sph is 0.0 diopter, the addition power AD is 2.0 diopter, and the base curve BC is 4.16 diopter. It is a progressive power lens. The progression zone starts from 11 mm above the lens geometric center O and ends at 8 mm below the center O. Therefore, the progressive zone length (intermediate length) is 19 mm.
[0079]
If the progressive addition lens belongs to a series of progressive addition lens series based on the progressive addition lens 20 mainly specialized for near vision, the width W _dt And width W _nt Satisfies the condition (12).
[0080]
[Expression 36]

[0081]
The progressive power lens designed so that the relationship between the clear vision area width of the distance portion and the clear vision area width of the near portion satisfies the condition (12) is a near-use progressive power lens having high transmission performance. is there. A person who wears the progressive-power lens can obtain an excellent wearing feeling particularly when observing an object at a short distance such as a tabletop.
[0082]
FIG. 15 is a list of transmission astigmatism distributions and transmission average refractive power distributions regarding several progressive addition lenses belonging to a series of progressive addition lenses having the progressive addition lens 20 as a reference design. Each progressive-power lens shown in FIG. 15 has a constant distance portion spherical refractive power Sph and a different base curve. Specifically, each progressive-power lens has a distance portion spherical power Sph of −2.0 diopter and an addition power AD of 2.0 diopter, and the base curve BC is 2.43 from the top in the figure. 3.21, 4.16, 4.78 (all units are diopters). Each progressive-power lens is designed so that the progressive zone starts from 11 mm above the lens geometric center O and ends at 8 mm below, like the progressive-power lens 20. FIG. 16 shows the above W _dt / W _nt It is the graph which showed how changes with respect to the change of a base curve. As can be seen from the aberration diagram shown in FIG. 15 and the graph shown in FIG. 16, the transmission astigmatism shows almost the same distribution tendency even if one or both of the spherical power of the distance portion and the base curve change. It can be seen that high optical performance is realized. FIG. 16 shows that lenses belonging to a series of progressive-power lenses having the progressive-power lens 20 as a reference design satisfy the condition (12).
[0083]
FIG. 17 shows an astigmatism distribution (FIG. 17A) and an average refractive power distribution (FIG. 17B) in the transmission performance of the progressive addition lens 30 as a comparative example with respect to the progressive addition lens 10 of the embodiment. FIG. 18 shows an astigmatism distribution (FIG. 18A) and an average refractive power distribution (FIG. 18B) in the surface performance of the progressive-power lens 30 as a comparative example.
[0084]
Similarly to the progressive-power lens 10, the progressive-power lens 30 has a distance portion spherical power Sph of 0.0 diopter, an addition power AD of 2.0 diopter, and a base curve BC of 3.21 diopter. The progressive zone starts from 11 mm above the lens geometric center O and ends at 8 mm below. In the comparative examples shown in FIGS. 15 and 16, astigmatism is adjusted by surface performance evaluation without optimization of transmission performance evaluation. As can be seen by comparing FIG. 17 and FIG. 18, the transmission and the performance on the surface are greatly different, and particularly not in the vicinity of the geometric center of the lens. Therefore, in the comparative example, in the wearing state, both the distance portion and the near portion have a narrow clear vision area width, and a wide field of view cannot be realized for the user. On the other hand, in the transmission aberration distribution of the progressive power lens 10 shown in FIG. 1, both the distance portion and the near portion have a wide clear viewing area width and realize high optical performance.
[0085]
The above is the embodiment of the present invention. In order to realize a progressive-power lens series that achieves both appearance performance and optical performance, it is necessary that transmission aberrations are optimized and the transmission aberration distribution hardly changes even if the base curve and spherical power change. It is. In this regard, according to the present invention, this is achieved by controlling the width of the clear vision area of surface astigmatism and transmission astigmatism with a certain condition.
[0086]
【The invention's effect】
As described above, according to the progressive-power lens series and the progressive-power lens of the present invention, in order to ensure a wide clear vision area, which is a substantial visual field of the wearer, and to keep the aesthetic appearance of the glasses good. It is possible to provide a progressive power lens in which the aberration balance is substantially unified even when the base curve and the distance portion spherical power are changed.
[Brief description of the drawings]
FIG. 1 shows an astigmatism distribution and an average refractive power distribution in transmission performance of a progressive-power lens according to a first embodiment of the present invention.
FIG. 2 shows an astigmatism distribution and an average refractive power distribution in the surface performance of the progressive-power lens according to the first embodiment of the present invention.
FIG. 3 is a diagram illustrating a characteristic amount of transmission performance in the progressive-power lens according to the embodiment.
FIG. 4 is a diagram illustrating a surface performance characteristic amount in the progressive-power lens according to the embodiment.
FIG. 5 shows transmission astigmatism distribution, transmission average refractive power distribution, and surface of several progressive addition lenses belonging to a series of progressive addition lenses based on the progressive addition lens of the first embodiment as a reference design; It is a list of astigmatism distribution and surface average refractive power distribution.
FIG. 6 shows that when the distance portion spherical refractive power Sph is set in the plus range, (W _ds / W _ns ) / (W _dt / W _nt ) Is a graph showing how the curve changes with respect to the change in the base curve.
FIG. 7 shows the above-mentioned W when the distance portion spherical refractive power Sph is set in the plus range. _ds / W _ns It is a graph which shows how changes with respect to the change of a base curve.
FIG. 8 shows transmission astigmatism distribution, transmission average refractive power distribution, and surface for several progressive power lenses belonging to a series of progressive power lenses based on the progressive power lens of the first embodiment as a reference design; It is a list of astigmatism distribution and surface average refractive power distribution.
FIG. 9 shows the above (W) when the distance portion spherical refractive power Sph is set in the negative range. _ds / W _ns ) / (W _dt / W _nt ) Is a graph showing how it changes in response to changes in the base curve
FIG. 10 shows the above-mentioned W when the distance portion spherical refractive power Sph is set in the minus range. _ds / W _ns It is a graph which shows how changes with respect to the change of a base curve.
FIG. 11 shows transmission astigmatism distribution, transmission average refractive power distribution, and surface for several progressive-power lenses belonging to a series of progressive-power lenses based on the progressive-power lens of the first embodiment as a reference design; It is a list of astigmatism distribution and surface average refractive power distribution.
FIG. 12 shows a constant spherical power Sph for distance and W _dt / W _nt It is a graph which shows how changes with respect to the change of a base curve.
FIG. 13 shows astigmatism distribution and average refractive power distribution in transmission performance of the progressive-power lens of the second embodiment.
FIG. 14 shows an astigmatism distribution and an average refractive power distribution in the surface performance of the progressive-power lens according to the second embodiment of the present invention.
FIG. 15 shows transmission astigmatism distribution and transmission average refractive power distribution regarding several progressive power lenses belonging to a series of progressive power lenses based on the progressive power lens according to the second embodiment of the present invention. It is a list.
FIG. 16 shows a constant spherical power Sph for distance and W _dt / W _nt It is the graph which showed how changes with respect to the change of a base curve.
FIG. 17 is a comparative example for the progressive-power lens according to the first embodiment of the present invention.
FIG. 18 is a comparative example for the progressive-power lens according to the first embodiment of the present invention.
[Explanation of symbols]
10 Progressive power lens
20 Progressive power lens
30 Progressive power lens (comparative example)
O Geometric center
X Reference line separating the vertical direction of the lens
Y Reference line separating the left and right direction of the lens
The distance W of the upper distance along the reference line Y from the geometric center of the DL lens _dt And W _ds Length to the position that defines
The near portion width W below the reference line Y from the geometric center of the NL lens _nt And W _ns Length to the position that defines
GL main line of sight
W _ds In the distance portion, the horizontal width of the region where the surface astigmatism is ½ of the addition power AD of the lens
W _ns Horizontal width of the region where the surface astigmatism is ½ of the addition power AD of the lens in the near portion
W _dt In the distance portion, the horizontal width of the region in which the astigmatism in the light beam transmitted through the lens is ½ of the addition power AD of the lens
W _nt Horizontal width of the region where the astigmatism in the light beam transmitted through the lens is ½ of the addition power AD of the lens in the near portion

Claims (16)

At least one surface of the lens has a distance portion having a refractive power for viewing a distance, a near portion having a refractive power for viewing a near side, and the distance portion and the A progressive surface with an intermediate part that continuously connects the refractive power of the near part, and a series of progressive power lens series with multiple types of base curves designed based on a lens with predetermined optical performance In the progressive power lens that belongs,
The base curve of the first lens arbitrarily extracted from the series is BC ₁ , the base curve of the second lens is BC ₂ (where BC ₁ <BC ₂ ), and the first lens and the second lens A progressive-power lens characterized by satisfying the following condition (1) when the spherical power Sph (unit: diopter) of the distance portion is +1 or more.

However, when the addition power, which is the difference between the refractive power of the distance portion and the refractive power of the near portion, is AD (unit: diopter), W _dt is upward from the geometric center in the distance portion. The horizontal width of the region where transmission astigmatism at a height apart by a predetermined distance is AD / 2,
W _nt is the horizontal width of the region where the transmission astigmatism is AD / 2 at a height that is a predetermined distance downward from the geometric center in the near portion,
W _ds is the width of the region where the surface astigmatism is AD / 2 at a height away from the geometric center by a predetermined distance in the distance portion,
W _ns represents the width of the region where the surface astigmatism is AD / 2 at a height that is a predetermined distance downward from the geometric center in the near portion. At least one surface of the lens has a distance portion having a refractive power for viewing a distance, a near portion having a refractive power for viewing a near side, and the distance portion and the A progressive surface with an intermediate part that continuously connects the refractive power of the near part, and a series of progressive power lens series with multiple types of base curves designed based on a lens with predetermined optical performance In the progressive power lens that belongs,
The base curve of the first lens arbitrarily extracted from the series is BC ₁ , the base curve of the second lens is BC ₂ (where BC ₁ <BC ₂ ), and the first lens and the second lens A progressive-power lens characterized by satisfying the following condition (2) when the spherical refractive power Sph (unit: diopter) of the distance portion is −1 or less.

However, when the addition power, which is the difference between the refractive power of the distance portion and the refractive power of the near portion, is AD (unit: diopter), W _dt is upward from the geometric center in the distance portion. The horizontal width of the region where transmission astigmatism at a height apart by a predetermined distance is AD / 2,
W _nt is the horizontal width of the region where the transmission astigmatism is AD / 2 at a height that is a predetermined distance downward from the geometric center in the near portion,
W _ds is the horizontal width of the region where the surface astigmatism is AD / 2 at a height away from the geometric center in the distance portion by a predetermined distance,
W _ns represents the width in the horizontal direction of the region in which the surface astigmatism is AD / 2 at a height that is a predetermined distance downward from the geometric center in the near portion. The progressive-power lens according to claim 1,
A progressive-power lens characterized by further satisfying the following condition (3).

The progressive-power lens according to claim 2,
Furthermore, the progressive-power lens characterized by satisfying the following condition (4):

At least one surface of the lens has a distance portion having a refractive power for viewing a distance, a near portion having a refractive power for viewing a near side, and the distance portion and the A progressive surface with an intermediate part that continuously connects the refractive power of the near part, and a series of progressive power lens series with multiple types of base curves designed based on a lens with predetermined optical performance In the progressive power lens that belongs,
The base curve of the first lens arbitrarily extracted from the series is BC ₁ , the base curve of the second lens is BC ₂ (where BC ₁ <BC ₂ ), and the first lens and the second lens A progressive-power lens characterized by satisfying the following condition (5) when the spherical refractive power Sph (unit: diopter) of the distance portion is not less than +1.

However, when the addition power, which is the difference between the refractive power of the distance portion and the refractive power of the near portion, is AD (unit: diopter), W _ds is upward from the geometric center in the distance portion. The horizontal width of the region where the surface astigmatism at a height apart by a predetermined distance is AD / 2,
W _ns represents the width in the horizontal direction of the region in which the surface astigmatism is AD / 2 at a height that is a predetermined distance downward from the geometric center in the near portion. At least one surface of the lens has a distance portion having a refractive power for viewing a distance, a near portion having a refractive power for viewing a near side, and the distance portion and the A progressive surface with an intermediate part that continuously connects the refractive power of the near part, and a series of progressive power lens series with multiple types of base curves designed based on a lens with predetermined optical performance In the progressive power lens that belongs,
The base curve of the first lens arbitrarily extracted from the series is BC ₁ , the base curve of the second lens is BC ₂ (where BC ₁ <BC ₂ ), and the first lens and the second lens A progressive-power lens characterized by satisfying the following condition (6) when the spherical power Sph (unit: diopter) of the distance portion is −1 or less.

However, when the addition power, which is the difference between the refractive power of the distance portion and the refractive power of the near portion, is AD (unit: diopter), W _ds is upward from the geometric center in the distance portion. The horizontal width of the region where the surface astigmatism at a height apart by a predetermined distance is AD / 2,
W _ns represents the width in the horizontal direction of the region in which the surface astigmatism is AD / 2 at a height that is a predetermined distance downward from the geometric center in the near portion. At least one surface of the lens has a distance portion having a refractive power for viewing a distance, a near portion having a refractive power for viewing a near side, and the distance portion and the A progressive surface with an intermediate part that continuously connects the refractive power of the near part, and a series of progressive power lens series with multiple types of base curves designed based on a lens with predetermined optical performance In the progressive power lens that belongs,
The base curve of the first lens arbitrarily extracted from the series is BC ₁ , the spherical refractive power of the distance portion of the first lens is Sph ₁ (unit: diopter), and the base curve of the second lens is BC _2. When the spherical refractive power of the distance portion of the second lens is Sph ₂ (unit: diopter), the following condition (7) is satisfied when BC ₁ ≠ BC ₂ or Sph ₁ ≠ Sph ₂ A progressive-power lens that is characterized.

However, when the addition power, which is the difference between the refractive power of the distance portion and the refractive power of the near portion, is AD (unit: diopter), W _dt is upward from the geometric center in the distance portion. The horizontal width of the region where transmission astigmatism at a height apart by a predetermined distance is AD / 2,
W _nt represents the width in the horizontal direction of the region where the transmission astigmatism is AD / 2 at a height that is a predetermined distance downward from the geometric center in the near portion. The progressive-power lens according to claim 7,
A progressive-power lens characterized by further satisfying the following condition (8) when BC ₁ ≠ BC ₂ and Sph ₁ = Sph ₂ = Sph _f :

The progressive-power lens according to claim 8,
A progressive-power lens characterized by further satisfying the following condition (9) when the Sph _f takes a value smaller than 0.

The progressive-power lens according to claim 7,
A progressive-power lens characterized by further having the following relationship when BC ₁ = BC ₂ = BC _f and Sph ₁ ≠ Sph ₂ .

In the progressive-power lens according to any one of claims 1 to 10,
In the distance portion, a horizontal width of a region where transmission astigmatism at a height away from the geometric center by a predetermined distance is AD / 2 is defined as a width W _dt. When the horizontal width of a region where transmission astigmatism at a height away from the center by a predetermined distance is AD / 2 is defined as a width W _nt , it further belongs to the series of progressive power lens series A progressive-power lens, wherein each progressive-power lens is designed to satisfy the following condition (11).

In the progressive-power lens according to any one of claims 1 to 10,
In the distance portion, a horizontal width of a region where transmission astigmatism at a height away from the geometric center by a predetermined distance is AD / 2 is defined as a width W _dt. When the horizontal width of a region where transmission astigmatism at a height away from the center by a predetermined distance is AD / 2 is defined as a width W _nt , it further belongs to the series of progressive power lens series A progressive-power lens , characterized in that each progressive-power lens is designed to satisfy the following condition (12).

The progressive-power lens in any one of Claims 1-12,
A progressive-power lens, wherein the intermediate portion has a length of 15 mm or more and 30 mm or less. In the progressive-power lens according to any one of claims 1 to 13 ,
The progressive power lens, wherein the progressive surface is an inner surface of the lens.   In the progressive-power lens according to any one of claims 1 to 14,
  In the distance portion, the position away from the geometric center by a predetermined distance is substantially coincident with the distance portion measurement reference point,
  A progressive-power lens characterized in that a position that is a predetermined distance away from the geometric center in the near portion substantially coincides with a near portion measurement reference point. In the progressive-power lens according to any one of claims 1 to 15 ,
The progressive power lens, wherein the predetermined distance is 15 mm.

Images